1. Field of the Invention
The present invention relates to a member separating apparatus and processing apparatus, member separating method, and semiconductor substrate manufacturing method.
2. Description of the Related Art
A substrate (SOI substrate) having an SOI (Silicon On Insulator) structure is known as a substrate having a single-crystal Si layer on an insulating layer. A device using this SOI substrate has many advantages that cannot be achieved by ordinary Si substrates. Examples of the advantages are as follows.
(1) The integration degree can be increased because dielectric isolation is easy.
(2) The radiation resistance can be increased.
(3) The operating speed of the device can be increased because the stray capacitance is small.
(4) No well step is necessary.
(5) Latch-up can be prevented.
(6) A completely depleted field-effect transistor can be formed by thin film formation.
Since an SOI structure has the above various advantages, researches have been made on its formation method for several decades.
As one SOI technology, the SOS (Silicon On Sapphire) technology by which Si is heteroepitaxially grown on a single-crystal sapphire substrate by CVD (Chemical Vapor Deposition) has been known for a long time. This SOS technology once earned a reputation as the most matured SOI technology. However, the SOS technology has not been put into practical use to date because, e.g., a large amount of crystal defects are produced by lattice mismatch in the interface between the Si layer and the underlying sapphire substrate, aluminum that forms the sapphire substrate mixes in the Si layer, the substrate is expensive, and it is difficult to obtain a large area.
A variety of SOI technologies have been introduced next to the SOS technology. Various techniques have been examined about these SOI technologies aiming at decreasing crystal defects and reducing the manufacturing cost. Examples of the techniques are as follows. First, oxygen ions are implanted into a substrate to form a buried oxide layer. Second, two wafers are bonded via an oxide film, and one of the wafers is polished or etched to leave a thin single-crystal Si layer on the oxide film. Third, hydrogen ions are implanted from the surface of an Si substrate having an oxide film to a predetermined depth, the substrate is bonded to another substrate, a thin single-crystal Si layer is left on the oxide film by heating or the like, and the bonded substrate (the other substrate) is peeled.
The present applicant has disclosed a new SOI technology in Japanese Patent Laid-Open No. 5-21338. In this technology, a first substrate prepared by forming a nonporous single-crystal layer on a single-crystal semiconductor substrate having a porous layer is bonded to a second substrate via an insulating layer (SiO2). After this, the substrates are separated at the porous layer, thereby transferring the nonporous single-crystal layer to the second substrate. Advantages of this technology are that the film thickness uniformity of the SOI layer is excellent, the crystal defect density in the SOI layer can be reduced, the surface planarity of the SOI layer is good, no expensive manufacturing apparatuses with special specifications are required, and SOI substrates having SOI films having a thickness of several hundred xc3x85 to 10 xcexcm can be manufactured by one manufacturing apparatus.
The present applicant has also disclosed, in Japanese Patent Laid-Open No. 7-302889, a technique of bonding the first and second substrates, separating the first substrate from the second substrate without destroying the first substrate, smoothing the surface of the separated first substrate, and forming a porous layer again to reuse the first substrate. In this technique, the first substrate is not wasted, and therefore, the manufacturing cost can be largely reduced, and the manufacturing process can also be simplified.
To facilitate mass production using the above techniques, factors to lower the yield must be minimized. For example, in a series of processes of separating a bonded substrate stack at a porous layer, it is important to avoid risks of substrate drop.
The present invention has been made in consideration of the above situation, and has as its object to provide a separating apparatus and method suitable to separate member such as substrates, a processing apparatus suitable to process members such as substrates, and a semiconductor substrate manufacturing method using the separating method.
According to the present invention, there is provided a member separating apparatus characterized by comprising manipulation means for changing a direction of a major surface of a member, and separation means for separating the member using a stream of a fluid, wherein the manipulation means has a function of manipulating the member to match the direction of the major surface with a first direction and a function of manipulating the member to match the direction of the major surface with a second direction.
In the separating apparatus, the manipulation means preferably receives the member with the major surface whose direction matches with the first direction, matches the direction of the major surface with the second direction, and moves the member to a position where the separation means can process the member, and also matches a direction of a major surface of at least one member of the members separated by the separation means with the first direction.
In the separating apparatus, the manipulation means preferably receives the member with the major surface whose direction matches with the first direction, matches the direction of the major surface with the second direction, and moves the member to a position where the separation means can process the member, and also matches directions of major surfaces of members of the members separated by the separation means with the first direction.
In the separating apparatus, the first and second directions are preferably substantially perpendicular to each other.
In the separating apparatus, the first direction is preferably a direction in which the major surface of the member is substantially horizontal.
In the separating apparatus, preferably, the member to be processed comprises a plate member, and the separation means cuts the plate member in a direction of plane to separate the member into two plate members.
In the separating apparatus, preferably, the second direction is a direction in which the major surface of the plate member is substantially vertical, and the separation means ejects the fluid toward the plate member in the vertical direction to separate the plate member into two plate members.
In the separating apparatus, the first direction is preferably a direction in which the major surface of the plate member is substantially horizontal.
In the separating apparatus, the manipulation means preferably comprises a pair of holding means for holding the plate member by sandwiching the member from two surface sides when the separation means separates the plate member.
In the separating apparatus, each of the holding means preferably comprises chuck means for chucking the plate member.
In the separating apparatus, preferably, the manipulation means comprises pivot means for pivoting at least one of the pair of holding means about a shaft parallel to a chuck surface of the chuck means, and the direction of the major surface of the plate member is changed by the pivot means.
In the separating apparatus, preferably, the manipulation means comprises pivot means for pivoting the pair of holding means about shafts parallel to chuck surfaces of the chuck means, and the direction of the major surface of the plate member is changed by the pivot means.
In the separating apparatus, the shaft as a pivot center of the holding means is preferably arranged at a position where the pair of holding means do not interfere with each other.
The separating apparatus preferably further comprises rotation means for rotating the member about a shaft perpendicular to the major surface.
In the separating apparatus, the rotation means preferably comprises means for rotating the member when the separation means separates the member.
In the separating apparatus, preferably, the separation means separates the member using a stream of a liquid, and the rotation means comprises means for rotating at least one of the members separated by the separation means to remove the liquid sticking to the member.
The separating apparatus preferably further comprises rotation means for rotating at least one of the pair of holding means about a shaft perpendicular to a holding surface.
In the separating apparatus, the rotation means preferably rotates the holding means when the separation mean separates the member.
In the separating apparatus, preferably, the separation means separates the member using a stream of a liquid, and the rotation means rotates the holding means to remove the liquid sticking to the member held by the holding means after the member is separated by the separation means.
The separating apparatus preferably further comprises a chamber for covering the apparatus.
In the separating apparatus, the chamber preferably has a shutter capable of opening/closing.
The separating apparatus preferably further comprises transfer means for transferring the member to be processed to the manipulation means and receiving the separated member from the manipulation means, the transfer means being arranged outside the chamber and transferring/receiving the member to/from the manipulation means while opening the shutter.
In the separating apparatus, the shutter is preferably closed at least when the member is separated by the separation means.
The separating apparatus preferably further comprises positioning means for positioning the member to be processed with respect to the manipulation means.
In the separating apparatus, preferably, the member to be separated has a fragile layer as a separation layer, and the fragile layer is substantially parallel to the major surface of the member.
According to the present invention, there is also provided a member processing apparatus characterized by comprising manipulation means for changing a direction of a major surface of a member, rotation means for rotating the member about a shaft perpendicular to the major surface, and processing means for processing the member while the rotation means is rotating the member, wherein the manipulation means receives the member with the major surface whose direction matches with a first direction, matches the direction of the major surface with a second direction, and moves the member to a position where the processing means can process the member, and also matches the direction of the major surface of the member which has been processed by the processing means with the first direction.
In the processing apparatus, the first and second directions are preferably substantially perpendicular to each other.
In the processing apparatus, the first direction is preferably a direction in which the major surface of the member is substantially horizontal.
In the processing apparatus, preferably, the processing means processes the member using a liquid, and the rotation means rotates the member to remove the liquid sticking to the member after the member is processed by the processing means.
According to the present invention, there is also provided a processing apparatus characterized by comprising holding means for holding a member, manipulation means for changing a direction of a holding surface of the holding means, processing means for processing the member held by the holding means, and rotation means for rotating the holding means holding the member about a shaft perpendicular to the holding surface when the processing means is processing and/or has processed the member, wherein the manipulation means matches the direction of the holding surface with a first direction when the holding means is to receive the member to be processed, matches the direction of the holding surface of the holding means with a second direction after the holding means receives and holds the member, and moves the holding means to a position where the processing means can process the member, and also matches the direction of the holding surface of the holding means with the first direction after processing by the processing means is complete.
In the processing apparatus, the first and second directions are preferably substantially perpendicular to each other.
In the processing apparatus, the first direction is preferably a direction in which the major surface of the member is substantially horizontal.
In the processing apparatus, preferably, the processing means processes the member using a liquid, and the rotation means rotates the member to remove the liquid sticking to the member after the member is processed by the processing means.
According to the present invention, there is provided a member separating method characterized by comprising the reception step of receiving a member with a major surface whose direction matches with a first direction, the manipulation step of matching the direction of the major surface of the member with a second direction, and the separation step of separating the member using a stream of a fluid.
The separating method preferably further comprises the second manipulation step of matching a direction of a major surface of at least one member of the members separated in the separation step with the first direction.
The separating method preferably further comprises the second manipulation step of matching directions of major surfaces of the members separated in the separation step with the first direction.
In the separating method, the first and second directions are preferably substantially perpendicular to each other.
In the separating method, the first direction is preferably a direction in which the major surface of the member is substantially horizontal.
In the separating method, preferably, the member to be processed comprises a plate member, and the separation step comprises cutting the plate member in a direction of plane to separate the member into two plate members.
In the separating method, preferably, the second direction is a direction in which the major surface of the plate member is substantially vertical, and the separation step comprises ejecting the fluid toward the plate member in the vertical direction to separate the plate member into two plate members.
In the separating method, the first direction is preferably a direction in which the major surface of the plate member is substantially horizontal.
In the separating method, the separation step preferably comprises holding the plate member by sandwiching the member from two surface sides.
In the separating method, the separation step preferably comprises separating the member using the stream of a fluid while rotating the member to be processed about a shaft perpendicular to the major surface.
In the separating method, preferably, the separation step comprises separating the member using a liquid, and the method further comprises rotating at least one of the members separated to remove the liquid sticking to the member after the member is separated in the separation step.
In the separating method, the separation step is preferably executed in a chamber to prevent the fluid from scattering.
In the separating method, preferably, the member to be processed has a fragile layer as a separation layer, and the fragile layer is substantially parallel to the major surface of the member.
In the separating method, the fragile layer preferably comprises a porous layer.
In the separating method, the fragile layer preferably comprises a layer having microcavity.
In the separating method, preferably, the member to be processed is prepared by bonding at least two plate members, and at least one of the two plate members comprises a semiconductor substrate.
In the separating method, the semiconductor substrate preferably comprises a single-crystal silicon substrate.
In the separating method, preferably, the member to be processed is prepared by bonding at least two plate members, and at least one of the two plate members comprises an insulating substrate.
In the separating method, the insulating substrate preferably comprises a quartz substrate.
In the separating method, preferably, the member to be processed is prepared by bonding at least two plate members, and at least one of the two plate members comprises a transparent substrate.
In the separating method, the member to be processed is preferably prepared by bonding a first substrate sequentially having a nonporous layer and a porous layer inward from a surface to a second substrate via the nonporous layer.
In the separating method, the nonporous layer preferably has a single-crystal silicon layer.
In the separating method, the nonporous layer preferably has an insulating layer on the single-crystal silicon layer.
In the separating method, the insulating layer is preferably formed from a silicon oxide.
In the separating method, the second substrate preferably comprises an insulating substrate.
In the separating method, the second substrate preferably comprises a transparent substrate.
In the separating method, the second substrate preferably comprises a quartz substrate.
In the separating method, the porous layer is preferably formed by anodizing a single-crystal silicon substrate.
In the separating method, the member to be processed is preferably prepared by bonding a second substrate to a surface of a first substrate incorporating a microcavity layer.
In the separating method, the microcavity layer is preferably formed by implanting ions into a single-crystal silicon substrate.
In the separating method, water is preferably used as the fluid.
According to the present invention, there is provided a semiconductor substrate manufacturing method characterized by comprising the steps of preparing a first substrate incorporating a porous layer or a microcavity layer, bonding the first substrate to a second substrate to prepare a bonded substrate stack, separating the bonded substrate stack into a first substrate side and a second substrate side using the porous layer or microcavity layer as a separation region by using any one of the above separating methods, and removing the porous layer or microcavity layer remaining on the second substrate side.
The semiconductor substrate manufacturing method preferably further comprises the step of, after the bonded substrate stack is separated, removing the porous layer or microcavity layer remaining on the first substrate side to reuse the first substrate.
In the semiconductor substrate manufacturing method, the porous layer is preferably formed by anodizing a semiconductor substrate.
In the semiconductor substrate manufacturing method, the microcavity layer is preferably formed by implanting ions in a semiconductor substrate.